EP3244437A1 - High-voltage direct-current temperature fuse - Google Patents
High-voltage direct-current temperature fuse Download PDFInfo
- Publication number
- EP3244437A1 EP3244437A1 EP15788772.0A EP15788772A EP3244437A1 EP 3244437 A1 EP3244437 A1 EP 3244437A1 EP 15788772 A EP15788772 A EP 15788772A EP 3244437 A1 EP3244437 A1 EP 3244437A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- current
- fuse
- thermal fuse
- voltage
- fusible alloy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H37/00—Thermally-actuated switches
- H01H37/74—Switches in which only the opening movement or only the closing movement of a contact is effected by heating or cooling
- H01H37/76—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
- H01H85/05—Component parts thereof
- H01H85/055—Fusible members
- H01H85/12—Two or more separate fusible members in parallel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H37/00—Thermally-actuated switches
- H01H37/02—Details
- H01H37/04—Bases; Housings; Mountings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H37/00—Thermally-actuated switches
- H01H37/74—Switches in which only the opening movement or only the closing movement of a contact is effected by heating or cooling
- H01H37/76—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material
- H01H37/761—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material with a fusible element forming part of the switched circuit
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/38—Means for extinguishing or suppressing arc
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/46—Circuit arrangements not adapted to a particular application of the protective device
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H37/00—Thermally-actuated switches
- H01H37/74—Switches in which only the opening movement or only the closing movement of a contact is effected by heating or cooling
- H01H37/76—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material
- H01H37/761—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material with a fusible element forming part of the switched circuit
- H01H2037/762—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material with a fusible element forming part of the switched circuit using a spring for opening the circuit when the fusible element melts
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/38—Means for extinguishing or suppressing arc
- H01H2085/381—Means for extinguishing or suppressing arc with insulating body insertable between the end contacts of the fusible element
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/30—Means for indicating condition of fuse structurally associated with the fuse
Definitions
- the invention relates to a high-voltage direct-current thermal fuse, especially relates to a high-voltage direct-current thermal fuse used for cutting off the arc in the high-voltage direct-current circuit.
- the thermal fuse is also called thermal fusible cutout, which is usually mounted in electrical appliances which are prone to generate heat. Once the appliance fails and generates heat, and when the temperature exceeds an abnormal temperature, the thermal fuse will automatically fuse to cut off the power supply to prevent the electric appliance from being on fire. In recent years, the thermal fuse is mounted on most household appliances which have the main function of heating, such as rice cookers, electric irons, and electric furnaces. When internal parts stop working, the power supply can be cut off in time by the thermal fuse to prevent the appliance from further damage, so as to avoid causing a fire.
- the thermal fuse is the same as the fuse we know well. It is usually just a path of power supply in the circuit. It will not fuse and does nothing to the circuit if the current does not exceed its rated value. It has a low resistance, a small power loss when normally working, and a low surface temperature. Only when the electrical appliance fails and generates an abnormal temperature will it fuse and cut off the power supply circuit.
- the thermal fuse plays a role in over-temperature protection in the power supply circuit when the temperature of the region where the thermal fuse is provided reaches the fusing-off temperature of the fusible alloy wire inside the thermal fuse.
- the fusible alloy wire shrinks towards leads on both ends to cut off the circuit, cutting off the current circuit to prevent other components in the circuit from being further damaged by the temperature anomaly.
- the thermal fuse is applied in many circuits that need over-temperature protection. Different circuits have different requirements for the thermal fuse.
- the embodiment of the invention is aimed at the problem that the existing thermal fuse cannot be directly used in a high-voltage circuit, providing a high-voltage direct-current thermal fuse to solve the problem of cutting off the arc in time.
- the high-voltage direct-current thermal fuse can be directly used in the high-voltage direct-current circuit.
- a high-voltage direct-current thermal fuse at least comprising a high-voltage low-current thermal fuse connected into a high-voltage direct-current circuit.
- the high-voltage low-current thermal fuse comprises a casing, a fusible alloy wire encapsulated in the casing, and two leads extending outside the casing.
- the fusible alloy wire is connected between the two leads.
- One of the leads is sequentially sleeved with an arc extinguishing sleeve and a spring.
- One end of the arc extinguishing sleeve contacts the fusible alloy wire, and the other end of the arc extinguishing sleeve contacts the spring.
- One end of the spring is connected to the internal end face of the casing, and the spring is in a compressed state.
- the high-voltage low-current thermal fuse has functions of high-voltage, low current arc extinguishing, and cutting-off protection. Since the fusible alloy wire has a certain stiffness under normal temperature, the arc extinguishing sleeve pushes against the fusible alloy wires wire under the effect of the compressing spring. The elasticity of the compressing spring in the compressed state is not sufficient to destroy the welding strength of the fusible alloy wire and leads.
- the fusible alloy wires has a good fluidity in a liquefied state.
- the arc extinguishing sleeve moves along the axis under the effect of the elasticity of the compressing spring to cut off the fusible alloy wire and to cover one lead, such that the discharging gap between the two leads is insulated to avoid the generation of a high-voltage arc.
- the embodiment of the invention also provides a high-voltage direct-current thermal fuse.
- the high-voltage direct-current thermal fuse includes the other thermal fuse which is connected in series into the high-voltage direct-current circuit.
- the high-voltage low-current thermal fuse is connected in parallel to both ends of the other thermal fuse. The fusing temperature of the high-voltage low-current thermal fuse is higher than that of the other thermal fuse.
- the high-voltage low-current thermal fuse is connected in series to a current fuse to form a primary branch.
- the primary branch is connected in parallel to both ends of the other thermal fuse.
- the resistance of the current fuse is more than that of the high-voltage low-current thermal fuse.
- the circuit to be protected when the circuit to be protected is a high-voltage, high-current circuit, after the temperature reaches the melting point of the other thermal fuse to fuse it, the current will go through the primary branch in parallel. Since the resistance of the current fuse is more than that of the high-voltage low-current thermal fuse, the current fuse fuses off first, and cuts off the primary branch in parallel.
- the circuit to be protected is a high-voltage, low-current circuit, after the temperature reaches the melting point of the other thermal fuse to fuse it, the current will go through the primary branch in parallel. At this time, since the low current cannot make the primary branch fuse, the temperature continues to increase till the melting point of the high-voltage low-current thermal fuse, so as to cause over-temperature high-voltage cutting-off, and this primary branch in parallel is cut off.
- the current fuse is a tube fuse, which includes a metal fusing wire inside the tube and a tube body with both ends having a metal connecting terminal.
- the current fuse is the N-type current fuse, which includes a fuse-link showing an N-type and two leads connecting to both ends of the fuse-link. The two leads extend from the top of the N-type of the fuse-link, which has a segment in parallel to each other.
- the breaking current of the high-voltage low-current thermal fuse is less than that of the N-type current fuse.
- the N-type fuse-link is encapsulated inside the casing.
- the casing is filled with arc extinguishing material, such as quartz sand.
- the N-type current fuse has the function of high-voltage high-current arc extinguishing.
- the electric field intensity generated by the leads in parallel is more than multiple times.
- the diffusion and recombination process of charged particles are more rapid under higher electric field intensity, making the gap between the electrode leads quickly recover to the insulation state, so as to achieve the aim of extinguishing the arc.
- the protection function of arc extinguishing multiple times more than that of the normal fuse is achieved.
- the other thermal fuse includes at least one fusible alloy wire.
- the fusible alloy wire is provided between the two leads. Specifically, it is welded between the two leads by soldering.
- the other thermal fuse in the embodiment of the invention includes an insulated casing and a base.
- the fusible alloy wire and two leads are arranged inside the cavity formed by the insulated casing and the base. Specifically, the fusible alloy wire is welded between the two leads. The ends of both leads extend outside the base.
- One or more pieces of fusible alloy wires can be provided between the two leads if necessary. The number thereof is not limited.
- the other thermal fuse of the embodiment of the includes two pieces of fusible alloy wires.
- the two pieces of fusible alloy wires are welded in parallel or crossways between the two leads to form a bridge-type connection.
- the opposite ends of two leads are outside the base.
- Symmetrical structure of two L-type leads contributes to the uniformity of the alloy wires in parallel and improves effective utilization of flow capacity in parallel.
- the high-voltage low-current thermal fuse is square-shell type or porcelain-tube type thermal fuse, or other alloy thermal fuse usually used in this field.
- the working principle of the alloy thermal fuse is the same. Different types of thermal fuses can be selected according to actual circuit needs to better apply in different circuits.
- the high-voltage direct-current thermal fuse of the embodiment of the invention also includes several (N) secondary branches.
- the secondary branch includes a high-voltage low-current thermal fuse and a current fuse that are connected in series sequentially.
- the structure of the high-voltage low-current thermal fuse and that of the current fuse are the same as those of the primary branch, which is not explained again here.
- N is equaled to 1
- the secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the primary branch.
- N is more than 1
- the Nth secondary branch is connected in parallel to the two ends of the high-voltage low-current thermal fuse in the (N-1)th secondary branch.
- high-voltage low-current thermal fuse can be expendably applied in the lightning protection module.
- the protection circuit is separated more effectively and timely to meet effective cutting off of the voltage.
- the invention makes an improvement to the internal structure of the existing thermal fuse to solve the problem that the existing thermal fuse cannot be directly used in the high-voltage circuit, so that the high-voltage low-current thermal fuse can be directly used in the high-voltage direct-current circuit for protection.
- the heat generated by the circuit is too high, it can cut off the circuit to avoid further damage to the electronic components and the occurrence of fire.
- the embodiment of the invention also provides an improved solution of the high-voltage direct-current thermal fuse.
- the circuit connecting manner in which the high-voltage low-current thermal fuse is connected in series to the current fuse and further connected in parallel to both ends of the other thermal fuse the voltage arc is extinguished timely.
- the arc can be extinguished and the circuit can be cut off in time, to prevent further damage to other components in the circuit resulting from the abnormal increase of temperature or burning caused by the arc.
- the high-voltage direct-current thermal fuse of the invention can be expanded using the manner of multi-parallel connecting to the high-voltage low-current thermal fuse, so that the high-voltage direct-current thermal fuse can be used in a lightning protection module.
- the high-voltage direct-current thermal fuse of the embodiment of the invention includes insulating base 101 and a large casing 103 provided thereon.
- Regular thermal fuse 100, current fuse 200, and high-voltage low-current thermal fuse 300 are provided inside a cavity formed between insulating base 101 and large casing 103.
- high-voltage low-current thermal fuse 300 is connected in series to current fuse 200 sequentially to form a primary branch. Then, the primary branch is connected in parallel to both ends of thermal fuse 100.
- thermal fuse 100 is connected in series into the high-voltage circuit to be protected, to provide the over-temperature protection for the high-voltage circuit.
- thermal fuse 100 specifically includes small casing 102 which is arranged on insulating base 101.
- Right lead of thermal fuse 105 and left lead of thermal fuse 106 are fixedly provided on both sides of insulating base 101.
- Fusible alloy wire 104 is provided inside the closed cavity formed by insulating base 101 and small casing 102. Fusible alloy wires 104 are welded between left lead 106 and right lead 105 which in the thermal fuse.
- Fig.2 shows, in the embodiment, two pieces of fusible alloy wires 104 provided in parallel are included specifically. In other embodiments, two or more pieces of fusible alloy wires that are in parallel or crossways can also be provided if necessary.
- left lead 106 and right lead 105 presents an L-shape, which are arranged along the central vertical axis of fusible alloy wires 104 symmetrically, and are injected to form a whole together with base 101.
- Two pieces of fusible alloy wires 104 in parallel are connected between two L-shape left leads 106 and right leads 105 to form a bridge-type connection.
- Fusible alloy wires 104 are made of low-melting conductive alloy material which is sensitive to temperature, and is coated by the fusing agent. When the temperature reaches the fusing temperature of fusible alloy wires 104, fusible alloy wires 104 is fused. With the effects of surface tension and fusing agent, fusible alloy wires 104 shrink towards both ends to become a ball and attach to the ends of two leads, so as to be the fusing switch point in the application circuit, cutting off the circuit.
- Current fuse 200 includes casing 201 and cover plate 202.
- Fuse 203 is arranged inside the cavity formed between casing 201 and cover plate 202.
- Fuse 203 is in a shape of bending N-type.
- Left lead 204 and right lead 205 are connected to both ends of fuse 203 respectively.
- Left lead 204 and right lead 205 are shaped to extend from the top of the N-type of fuse 203 and have a segment in parallel with each other.
- Left lead 204 and right lead 205 pass through the via holes on casing 201 respectively, extending out of casing 201 and exposing to the outside, so as to be electric connection point connecting fuse 203 to outside.
- Fuse 203 suspends in the N-type cavity, without contacting internal cavity wall of the N-type cavity.
- fuse 203 inside current fuse 200 is in a shape of bending N-type
- current fuse 200 is called N-type current fuse.
- the N-type cavity also can be filled with arc extinguishing materials such as quartz sand, to make heat balance of fuse 203 become stable.
- the breaking current of the high-voltage low-current thermal fuse is less than that of the N-type current fuse.
- the breaking is from the center point of the N-type towards both sides.
- An arc is inevitably generated at the breaking point of fuse 203, such that a large number of charged particles are generated from the arc.
- the electric field intensity generated by left lead 204 and right lead 205 that are in parallel in the current fuse is more than multiple times.
- the diffusion and recombination process of charged particles are more rapid under high electric field intensity, making the gap between electrode leads quickly recover to the insulation state, achieving the aim of extinguishing the arc.
- the arc extinguishing protection effect which is multiple times more than that of the normal fuse is achieved, and a safety protection for circuit and human is realized.
- high-voltage low-current thermal fuse 300 is a disposable non-resettable fusing device.
- the square-shell type thermal fuse is used, which includes the shell consisting of casing 301 and base 302, temperature sensing member sealed inside the casing (e.g., fusible alloy wires 303 which has a low melting point and a good temperature sensitivity, wherein fusible alloy wires 303 is coated with fusing agent), and two leads extending outside the shell.
- the reference numbers of the two leads are 306, 307 respectively.
- fusible alloy wires 303 are welded between left lead 306 and right lead 307. As Fig.2 shows, left lead 306 and right lead 307 are provided in parallel with each other.
- the axes of two leads are perpendicular to fusible alloy wires 303 respectively.
- Fusible alloy wires 303 are specifically welded on the top of axes of left lead 306 and right lead 307. After the axes of left lead 306 and right lead 307 pass through the via holes on base 302, they are bent and extend along the direction which is away from fusible alloy wires 303. Each extending lead is exposed to outside base 302 as an external electric connection point.
- a round cavity is further provided inside base 302 where compressing spring 305 and arc extinguishing sleeve 304 are located.
- Arc extinguishing sleeve 304 and compressing spring 305 are positioned to surround the axis of high-voltage left lead 306.
- One end of compressing spring 305 which in a compressed state is connected to internal end face of the round cavity of base 302, and the other end contacts arc extinguishing sleeve 304.
- the end opposite to compressing spring 305 of arc extinguishing sleeve 304 contacts fusible alloy wires 303.
- fusible alloy wires 303 Since fusible alloy wires 303 has a certain stiffness under normal temperature, arc extinguishing sleeve 304 pushes against fusible alloy wires 303 under the effect of compressing spring 305.
- the elasticity of the compressing spring which is configured in the compressed state, is not sufficient to destroy the welding strength of fusible alloy wires 303 and high-voltage left lead 306 and high-voltage right lead 307.
- High-voltage low-current thermal fuse 300 mainly functions as over-temperature and high-voltage cutting off protection.
- the temperature of the region where high-voltage low-current thermal fuse 300 is located reaches the fusing temperature of fusible alloy wires 303 inside high-voltage low-current thermal fuse 300, fusible alloy wires 303 melt.
- fusible alloy wires 303 shrink towards both ends and become a ball, attaching to the ends of two leads (whose reference numbers are 306 and 307 respectively).
- Fig.3 shows a circuit diagram of Embodiment 1 of the invention.
- current fuse 200 is connected in series to high-voltage low-current thermal fuse 300, and is subsequently connected in parallel to regular thermal fuse 100.
- the left and right leads of regular thermal fuse 100 are connected in series in the high-voltage circuit to be protected to provide the over-temperature protection for the high-voltage circuit.
- left lead 204 of current fuse 200 is connected to right lead 307 of high-voltage low-current thermal fuse 300 to form electric connection in series.
- Right lead 205 of current fuse 200 and left lead 306 of high-voltage low-current thermal fuse 300 are respectively connected to right lead 105 and left lead 106 of thermal fuse 100 to form an electric connection in parallel.
- Right lead 105 and left lead 106 of regular thermal fuse 100 is connected to the high-voltage circuit, to be in series in the circuit which needs protection, so as to provide the over-temperature protection for the high-voltage circuit.
- the fusing temperature of traditional thermal fuse 100 should be configured to be less than the fusing temperature of high-voltage low-current thermal fuse 300.
- the resistance of fuse-link in the current fuse should be configured to be more than that of high-voltage low-current thermal fuse.
- fusible alloy wires 104 fuse off and shrink towards left and right leads on both ends. Due to the existence of the parallel circuit, the cutting off of fusible alloy wires 104 will not generate arcing.
- the current will go through the primary branch which is connected in parallel with thermal fuse 100, that is, the branch formed by current fuse 200 connected in series with high-voltage low-current thermal fuse 300. Since the resistance of fuse 203 in current fuse 200 is more than that of high-voltage low-current thermal fuse 300, fuse 203 fuses off first to cut off the parallel circuit.
- Arc extinguishing sleeve 304 covers high-voltage left lead 306 to insulate the discharging gap between high-voltage left lead 306 and high-voltage right lead 307, so as to cut off the parallel circuit to prevent further damages to the electric appliance resulted from abnormal increasing of temperature or burning caused by the arc.
- Fig.4 shows the circuit schematic diagram of Embodiment 2 of the invention.
- the high-voltage direct-current thermal fuse is composed of thermal fuse 100, current fuse 200, and high-voltage low-current thermal fuse 300 as the same as those in Embodiment 1.
- high-voltage low-current thermal fuse 300 is sequentially connected in series to current fuse 200 to form the primary branch.
- the primary branch is connected in parallel to both ends of thermal fuse 100.
- Thermal fuse 100 is connected in series to the high-voltage circuit to be protected, so as to provide the over-temperature protection for the high-voltage circuit, which is not explained again here.
- the high-voltage direct-current thermal fuse also includes N secondary branches, and each secondary branch includes the high-voltage low-current thermal fuse sequentially connected in series to the current fuse.
- the structure of the high-voltage low-current thermal fuse and that of the current fuse are the same as those of the primary branch, which is not explained again here.
- N is equal to 1
- the secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the primary branch.
- N is more than 1
- the Nth secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse which in the (N-1)th secondary branch.
- Fig.4 shows, Fig.4 includes two secondary branches. N is equal to 2.
- the first secondary branch includes high-voltage low-current thermal fuse 300' and current fuse 200' that are connected to each other in series sequentially.
- the second secondary branch includes high-voltage low-current thermal fuse 300" and current fuse 200" that are connected to each other in series sequentially.
- the first secondary branch is connected in parallel to both ends of high-voltage low-current thermal fuse 300 in the primary branch.
- the second secondary branch is connected in parallel to both ends of high-voltage low-current thermal fuse 300' in the first secondary branch.
- the number of the secondary branches is not limited to two in Embodiment 2, and can also be more.
- the next level of secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the last level of secondary branch.
- the high-voltage low-current thermal fuse can be expendably applied in lightning protection module.
- the protection circuit is separated more effectively and timely to meet effective cutting off of the voltage.
- the high-voltage low-current thermal fuse in above Embodiment 1 and Embodiment 2 can both use the porcelain-tube type thermal fuse.
- the porcelain-tube type thermal fuse includes insulated porcelain tube, inside which fusible alloy wires that can melt at a predetermined temperature are encapsulated.
- the fusible alloy wires are welded between the right lead and left lead that are axisymmetric.
- the ends of two leads respectively extend outside the insulated porcelain tube in the direction which is away from the fusible alloy wires.
- any of the two leads can be sleeved by an arc extinguishing sleeve and a compressing spring.
- One end of the arc extinguishing sleeve contacts the fusible alloy wires, and the other end contacts the spring.
- One end of the spring is connected to the internal end face of the insulated porcelain tube in the compressed state.
- the elasticity of the spring which in configured in a compressed state is not sufficient to destroy the welding strength between the fusible alloy wires and left, right leads.
- Other settings are the same as those in Embodiment 1 or 2, which is not explained again here.
- high-voltage low-current thermal fuse 300 in the embodiment of the invention can be used in the high-voltage direct-current circuit alone (e.g. connecting in series into the high-voltage direct-current circuit).
- the circuit to be protected is the high-voltage direct-current circuit
- fusible alloy wires 303 in the high-voltage direct-current thermal fuse 300 fuse off and shrink towards both ends to become a ball, attaching to the ends of the leads whose reference numbers are 306, 307 respectively.
- liquidized fusible alloy wires 303 has a good fluidity.
- Arc extinguishing sleeve 304 moves along the axis to cut off fusible alloy wires 303 under the effect of the elasticity of compressing spring 305.
- Arc extinguishing sleeve 304 covers high-voltage left lead 306 to insulate the special discharging gap between the high-voltage left lead 306 and the high-voltage right lead 307, so as to cut off the parallel circuit to prevent further damages to other components in the circuit resulted from the abnormal increasing of temperature or burning caused by the arc.
- the manner of using a regular thermal fuse connected in parallel to a current fuse can also be used to apply in the high-voltage direct-current circuit.
- the effect of the manner may not be optimal, it can realize the function of circuit cutting-off and arc extinguishing. If outside temperature reaches the fusing temperature of thermal fuse 100, the cutting-off of fusible alloy wires 104 fuse off and shrink towards the right and left leads at both ends. Due to the existence of parallel circuit, the cutting-off of fusible alloy wires 104 will not generate the arc. The current will go through the current fuse connected in parallel to thermal fuse 100. When the current reaches a certain intensity and a certain temperature, fuse 203 of current fuse 200 will fuse off automatically to cut off the current, so as to achieve the function of protecting the circuit to operate safely.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Fuses (AREA)
Abstract
Description
- The invention relates to a high-voltage direct-current thermal fuse, especially relates to a high-voltage direct-current thermal fuse used for cutting off the arc in the high-voltage direct-current circuit.
- The thermal fuse is also called thermal fusible cutout, which is usually mounted in electrical appliances which are prone to generate heat. Once the appliance fails and generates heat, and when the temperature exceeds an abnormal temperature, the thermal fuse will automatically fuse to cut off the power supply to prevent the electric appliance from being on fire. In recent years, the thermal fuse is mounted on most household appliances which have the main function of heating, such as rice cookers, electric irons, and electric furnaces. When internal parts stop working, the power supply can be cut off in time by the thermal fuse to prevent the appliance from further damage, so as to avoid causing a fire. The thermal fuse is the same as the fuse we know well. It is usually just a path of power supply in the circuit. It will not fuse and does nothing to the circuit if the current does not exceed its rated value. It has a low resistance, a small power loss when normally working, and a low surface temperature. Only when the electrical appliance fails and generates an abnormal temperature will it fuse and cut off the power supply circuit.
- The thermal fuse plays a role in over-temperature protection in the power supply circuit when the temperature of the region where the thermal fuse is provided reaches the fusing-off temperature of the fusible alloy wire inside the thermal fuse. With the help of the fusing agent, the fusible alloy wire shrinks towards leads on both ends to cut off the circuit, cutting off the current circuit to prevent other components in the circuit from being further damaged by the temperature anomaly. Thus, the thermal fuse is applied in many circuits that need over-temperature protection. Different circuits have different requirements for the thermal fuse.
- In a direct current circuit which has a high voltage level of 400V or above, during the process of fusing of the fusible alloy wire of traditional thermal fuse, the shrinking speed of the fusible alloy wire is slow and the gap between the two leads is too short, an arc is generated, resulting in that the circuit cannot be cut off in time. The circuit can be burned down due to the occurrence of the arc together with the high-temperature burning. Thus, if the existing thermal fuse is used in a direct current circuit which has a voltage level of 400V or above, it not only cannot cut off the circuit in time to protect the circuit, but also may introduce unnecessary problems.
- The embodiment of the invention is aimed at the problem that the existing thermal fuse cannot be directly used in a high-voltage circuit, providing a high-voltage direct-current thermal fuse to solve the problem of cutting off the arc in time. The high-voltage direct-current thermal fuse can be directly used in the high-voltage direct-current circuit.
- Specific solution is as follows: a high-voltage direct-current thermal fuse at least comprising a high-voltage low-current thermal fuse connected into a high-voltage direct-current circuit. The high-voltage low-current thermal fuse comprises a casing, a fusible alloy wire encapsulated in the casing, and two leads extending outside the casing. The fusible alloy wire is connected between the two leads. One of the leads is sequentially sleeved with an arc extinguishing sleeve and a spring. One end of the arc extinguishing sleeve contacts the fusible alloy wire, and the other end of the arc extinguishing sleeve contacts the spring. One end of the spring is connected to the internal end face of the casing, and the spring is in a compressed state.
- The high-voltage low-current thermal fuse has functions of high-voltage, low current arc extinguishing, and cutting-off protection. Since the fusible alloy wire has a certain stiffness under normal temperature, the arc extinguishing sleeve pushes against the fusible alloy wires wire under the effect of the compressing spring. The elasticity of the compressing spring in the compressed state is not sufficient to destroy the welding strength of the fusible alloy wire and leads. Thus, when the high-voltage low-current thermal fuse is connected into the high-voltage direct-current circuit, and if the temperature reaches the liquidus point of the fusible alloy wires to liquefy the fusible alloy wires, the fusible alloy wires has a good fluidity in a liquefied state. The arc extinguishing sleeve moves along the axis under the effect of the elasticity of the compressing spring to cut off the fusible alloy wire and to cover one lead, such that the discharging gap between the two leads is insulated to avoid the generation of a high-voltage arc.
- As a preferable embodiment, in order to better apply in the high-voltage direct-current circuit to cut off the arc, the embodiment of the invention also provides a high-voltage direct-current thermal fuse. The high-voltage direct-current thermal fuse includes the other thermal fuse which is connected in series into the high-voltage direct-current circuit. The high-voltage low-current thermal fuse is connected in parallel to both ends of the other thermal fuse. The fusing temperature of the high-voltage low-current thermal fuse is higher than that of the other thermal fuse.
- As a preferable embodiment, the high-voltage low-current thermal fuse is connected in series to a current fuse to form a primary branch. The primary branch is connected in parallel to both ends of the other thermal fuse. The resistance of the current fuse is more than that of the high-voltage low-current thermal fuse.
- According to the above arrangements, when the circuit to be protected is a high-voltage, high-current circuit, after the temperature reaches the melting point of the other thermal fuse to fuse it, the current will go through the primary branch in parallel. Since the resistance of the current fuse is more than that of the high-voltage low-current thermal fuse, the current fuse fuses off first, and cuts off the primary branch in parallel. When the circuit to be protected is a high-voltage, low-current circuit, after the temperature reaches the melting point of the other thermal fuse to fuse it, the current will go through the primary branch in parallel. At this time, since the low current cannot make the primary branch fuse, the temperature continues to increase till the melting point of the high-voltage low-current thermal fuse, so as to cause over-temperature high-voltage cutting-off, and this primary branch in parallel is cut off.
- As a preferable embodiment, the current fuse is a tube fuse, which includes a metal fusing wire inside the tube and a tube body with both ends having a metal connecting terminal. Preferably, the current fuse is the N-type current fuse, which includes a fuse-link showing an N-type and two leads connecting to both ends of the fuse-link. The two leads extend from the top of the N-type of the fuse-link, which has a segment in parallel to each other. Among others, when the high-voltage low-current thermal fuse is used to be connected in parallel to the N-type current fuse, the breaking current of the high-voltage low-current thermal fuse is less than that of the N-type current fuse. As a preferable embodiment, the N-type fuse-link is encapsulated inside the casing. The casing is filled with arc extinguishing material, such as quartz sand. The N-type current fuse has the function of high-voltage high-current arc extinguishing. Compared to the linear cavity structure production, at the fusing-off moment, in the current fuse with the N-type fuse-link the electric field intensity generated by the leads in parallel is more than multiple times. The diffusion and recombination process of charged particles are more rapid under higher electric field intensity, making the gap between the electrode leads quickly recover to the insulation state, so as to achieve the aim of extinguishing the arc. Thus, the protection function of arc extinguishing multiple times more than that of the normal fuse is achieved.
- As a preferable embodiment, the other thermal fuse includes at least one fusible alloy wire. The fusible alloy wire is provided between the two leads. Specifically, it is welded between the two leads by soldering.
- The other thermal fuse in the embodiment of the invention includes an insulated casing and a base. The fusible alloy wire and two leads are arranged inside the cavity formed by the insulated casing and the base. Specifically, the fusible alloy wire is welded between the two leads. The ends of both leads extend outside the base. One or more pieces of fusible alloy wires can be provided between the two leads if necessary. The number thereof is not limited.
- As a preferable embodiment, the other thermal fuse of the embodiment of the includes two pieces of fusible alloy wires. The two pieces of fusible alloy wires are welded in parallel or crossways between the two leads to form a bridge-type connection. The opposite ends of two leads are outside the base. Symmetrical structure of two L-type leads contributes to the uniformity of the alloy wires in parallel and improves effective utilization of flow capacity in parallel.
- As a preferable solution, the high-voltage low-current thermal fuse is square-shell type or porcelain-tube type thermal fuse, or other alloy thermal fuse usually used in this field. The working principle of the alloy thermal fuse is the same. Different types of thermal fuses can be selected according to actual circuit needs to better apply in different circuits.
- As a preferable embodiment, the high-voltage direct-current thermal fuse of the embodiment of the invention also includes several (N) secondary branches. The secondary branch includes a high-voltage low-current thermal fuse and a current fuse that are connected in series sequentially. Among others, the structure of the high-voltage low-current thermal fuse and that of the current fuse are the same as those of the primary branch, which is not explained again here. When N is equaled to 1, the secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the primary branch. When N is more than 1, the Nth secondary branch is connected in parallel to the two ends of the high-voltage low-current thermal fuse in the (N-1)th secondary branch. Using the manner of multi-parallel connecting to the high-voltage low-current thermal fuse, high-voltage low-current thermal fuse can be expendably applied in the lightning protection module. Thus, the protection circuit is separated more effectively and timely to meet effective cutting off of the voltage.
- The invention makes an improvement to the internal structure of the existing thermal fuse to solve the problem that the existing thermal fuse cannot be directly used in the high-voltage circuit, so that the high-voltage low-current thermal fuse can be directly used in the high-voltage direct-current circuit for protection. When the heat generated by the circuit is too high, it can cut off the circuit to avoid further damage to the electronic components and the occurrence of fire.
- Furthermore, the embodiment of the invention also provides an improved solution of the high-voltage direct-current thermal fuse. By the circuit connecting manner in which the high-voltage low-current thermal fuse is connected in series to the current fuse and further connected in parallel to both ends of the other thermal fuse, the voltage arc is extinguished timely. As a result, in conditions of both high-voltage low-current, and high-voltage high-current, the arc can be extinguished and the circuit can be cut off in time, to prevent further damage to other components in the circuit resulting from the abnormal increase of temperature or burning caused by the arc. In addition, the high-voltage direct-current thermal fuse of the invention can be expanded using the manner of multi-parallel connecting to the high-voltage low-current thermal fuse, so that the high-voltage direct-current thermal fuse can be used in a lightning protection module.
- Referring to the following drawings, further descriptions are made to the invention, wherein:
-
Fig.1 is a perspective partial profile diagram of Embodiment 1 of the invention. -
Fig.2 is a perspective explosive view of Embodiment 1 of the invention. -
Fig.3 is a circuit schematic diagram of Embodiment 1 of the invention. -
Fig.4 is a circuit schematic diagram of Embodiment 2 of the invention. - In the text, the same reference numbers denote the same parts. When describing the drawings, not all the parts or components shown need to be discussed together with the corresponding drawings. Among others, the reference numbers are as follows:
- 100-another thermal fuse/conventional temperature fuse, 101-insulating base, 102-small casing, 103-large casing, 104-fusible alloy wires, 105-left lead of the thermal fuse, 106-right lead of the thermal fuses;
- 200-current fuse, 201-casing, 202-cover plate, 203-fuse, 204-left lead of the current fuse, 205-right lead of the current fuse;
- 300-high-voltage low-current thermal fuse, 301-casing, 302-base, 303- fusible alloy wires, 304-arc extinguishing sleeve, 305-compressing spring, 306-left lead of the high-voltage low-current thermal fuse, 307-right lead of the high-voltage low-current thermal fuse.
- Hereinafter, embodiments of the invention will be described more completely by means of embodiments referring to the drawings. Among others, only some embodiments have been shown. However, in practice, embodiments of the invention can be embodied in many different forms, but not limited to the embodiments in the text. These embodiments are provided for the purpose of better understanding of the invention.
-
Fig.1 andFig.2 respectively show the perspective partial profile diagram and the perspective explosive view of Embodiment 1 of the invention. AsFig.1 ,Fig.2 shows, the high-voltage direct-current thermal fuse of the embodiment of the invention includes insulatingbase 101 and alarge casing 103 provided thereon. Regularthermal fuse 100,current fuse 200, and high-voltage low-currentthermal fuse 300 are provided inside a cavity formed between insulatingbase 101 andlarge casing 103. Among others, high-voltage low-currentthermal fuse 300 is connected in series tocurrent fuse 200 sequentially to form a primary branch. Then, the primary branch is connected in parallel to both ends ofthermal fuse 100. Next,thermal fuse 100 is connected in series into the high-voltage circuit to be protected, to provide the over-temperature protection for the high-voltage circuit. - Please refer to
Fig.2 ,thermal fuse 100 specifically includessmall casing 102 which is arranged on insulatingbase 101. Right lead ofthermal fuse 105 and left lead ofthermal fuse 106 are fixedly provided on both sides of insulatingbase 101. Fusible alloy wire 104 is provided inside the closed cavity formed by insulatingbase 101 andsmall casing 102. Fusible alloy wires 104 are welded betweenleft lead 106 andright lead 105 which in the thermal fuse. AsFig.2 shows, in the embodiment, two pieces of fusible alloy wires 104 provided in parallel are included specifically. In other embodiments, two or more pieces of fusible alloy wires that are in parallel or crossways can also be provided if necessary. It should be noted that in specific implementation process, the number of pieces of fusible alloy wires and the specific cross-sectional area of each piece of fusible alloy wires can be adaptively adjusted by one skilled in the art according to various current flow rates of the thermal fuse. In the embodiment,left lead 106 andright lead 105 presents an L-shape, which are arranged along the central vertical axis of fusible alloy wires 104 symmetrically, and are injected to form a whole together withbase 101. Two pieces of fusible alloy wires 104 in parallel are connected between two L-shape left leads 106 and right leads 105 to form a bridge-type connection. Also, the terminals ofleft lead 106 andright lead 105 reach out of insulatingbase 101, extending in the direction which is opposite to fusible alloy wires 104 respectively. Fusible alloy wires 104 are made of low-melting conductive alloy material which is sensitive to temperature, and is coated by the fusing agent. When the temperature reaches the fusing temperature of fusible alloy wires 104, fusible alloy wires 104 is fused. With the effects of surface tension and fusing agent, fusible alloy wires 104 shrink towards both ends to become a ball and attach to the ends of two leads, so as to be the fusing switch point in the application circuit, cutting off the circuit. -
Current fuse 200 includescasing 201 andcover plate 202. Fuse 203 is arranged inside the cavity formed betweencasing 201 andcover plate 202. Among others,Fuse 203 is in a shape of bending N-type.Left lead 204 andright lead 205 are connected to both ends offuse 203 respectively.Left lead 204 andright lead 205 are shaped to extend from the top of the N-type offuse 203 and have a segment in parallel with each other.Left lead 204 andright lead 205 pass through the via holes on casing 201 respectively, extending out ofcasing 201 and exposing to the outside, so as to be electric connectionpoint connecting fuse 203 to outside. Fuse 203 suspends in the N-type cavity, without contacting internal cavity wall of the N-type cavity. Sincefuse 203 insidecurrent fuse 200 is in a shape of bending N-type,current fuse 200 is called N-type current fuse. In order to improve the effectiveness of extinguishing arc, the N-type cavity also can be filled with arc extinguishing materials such as quartz sand, to make heat balance offuse 203 become stable. Among others, when the high-voltage low-current thermal fuse is used to connected in series to N-type current fuse, the breaking current of the high-voltage low-current thermal fuse is less than that of the N-type current fuse. - When
current fuse 200 is powered on, the temperature offuse 203 will increase because of the heat generated from current conversion. When loading normal working current or allowed over-loading current, the heat generated by the current, and the heat which is dissipated by means of radiating, convecting, conducting, and etc. throughfuse 203, casing 201, and surrounding environment can reach a balance gradually. If the heat dissipating speed cannot keep up with the heat generating speed, those heat will accumulate on the fuse-link to make the temperature offuse 203 increase. Once the temperature reaches or goes beyond the melting point offuse 203, it will be liquefied or vaporized to cut off the circuit. - At the fusing moment of
fuse 203, usually, the breaking is from the center point of the N-type towards both sides. An arc is inevitably generated at the breaking point offuse 203, such that a large number of charged particles are generated from the arc. At the same time, the electric field intensity generated byleft lead 204 andright lead 205 that are in parallel in the current fuse is more than multiple times. The diffusion and recombination process of charged particles are more rapid under high electric field intensity, making the gap between electrode leads quickly recover to the insulation state, achieving the aim of extinguishing the arc. Thus, the arc extinguishing protection effect which is multiple times more than that of the normal fuse is achieved, and a safety protection for circuit and human is realized. - Please refer to
Fig.2 , high-voltage low-currentthermal fuse 300 is a disposable non-resettable fusing device. In the embodiment, the square-shell type thermal fuse is used, which includes the shell consisting ofcasing 301 andbase 302, temperature sensing member sealed inside the casing (e.g.,fusible alloy wires 303 which has a low melting point and a good temperature sensitivity, whereinfusible alloy wires 303 is coated with fusing agent), and two leads extending outside the shell. The reference numbers of the two leads are 306, 307 respectively. Among others,fusible alloy wires 303 are welded betweenleft lead 306 andright lead 307. AsFig.2 shows,left lead 306 andright lead 307 are provided in parallel with each other. The axes of two leads are perpendicular tofusible alloy wires 303 respectively.Fusible alloy wires 303 are specifically welded on the top of axes ofleft lead 306 andright lead 307. After the axes ofleft lead 306 andright lead 307 pass through the via holes onbase 302, they are bent and extend along the direction which is away fromfusible alloy wires 303. Each extending lead is exposed tooutside base 302 as an external electric connection point. - A round cavity is further provided inside
base 302 where compressingspring 305 andarc extinguishing sleeve 304 are located.Arc extinguishing sleeve 304 and compressingspring 305 are positioned to surround the axis of high-voltageleft lead 306. One end of compressingspring 305 which in a compressed state is connected to internal end face of the round cavity ofbase 302, and the other end contactsarc extinguishing sleeve 304. The end opposite to compressingspring 305 ofarc extinguishing sleeve 304 contactsfusible alloy wires 303. Sincefusible alloy wires 303 has a certain stiffness under normal temperature,arc extinguishing sleeve 304 pushes againstfusible alloy wires 303 under the effect of compressingspring 305. The elasticity of the compressing spring, which is configured in the compressed state, is not sufficient to destroy the welding strength offusible alloy wires 303 and high-voltageleft lead 306 and high-voltageright lead 307. - High-voltage low-current
thermal fuse 300 mainly functions as over-temperature and high-voltage cutting off protection. When the temperature of the region where high-voltage low-currentthermal fuse 300 is located reaches the fusing temperature offusible alloy wires 303 inside high-voltage low-currentthermal fuse 300,fusible alloy wires 303 melt. Also, with the help of surface tension and a fusing agent (e.g. special resin),fusible alloy wires 303 shrink towards both ends and become a ball, attaching to the ends of two leads (whose reference numbers are 306 and 307 respectively). Since the circuit where it is located is a high-voltage circuit, the speed of shrinkage offusible alloy wires 303 is too slow and the gap between high-voltageleft lead 306 andright lead 307 is too short, an arc is likely to be generated. With the generation of a high-voltage arc, liquefiedfusible alloy wires 303 has a good fluidity. With the help of the elasticity of compressingspring 305,arc extinguishing sleeve 304 moves along the axis to cut offfusible alloy wires 303.Arc extinguishing sleeve 304 covers high-voltageleft lead 306 to insulate the discharging gap between high-voltageleft lead 306 and high-voltageright lead 307. Thus, the current circuit is cut off to prevent further damage to other components in the circuit resulting from abnormal increases of temperature or burning caused by the arc. -
Fig.3 shows a circuit diagram of Embodiment 1 of the invention. AsFig.3 shows,current fuse 200 is connected in series to high-voltage low-currentthermal fuse 300, and is subsequently connected in parallel to regularthermal fuse 100. Then the left and right leads of regularthermal fuse 100 are connected in series in the high-voltage circuit to be protected to provide the over-temperature protection for the high-voltage circuit. More specifically, afterleft lead 204 ofcurrent fuse 200 is connected toright lead 307 of high-voltage low-currentthermal fuse 300 to form electric connection in series.Right lead 205 ofcurrent fuse 200 and leftlead 306 of high-voltage low-currentthermal fuse 300 are respectively connected toright lead 105 and leftlead 106 ofthermal fuse 100 to form an electric connection in parallel.Right lead 105 and leftlead 106 of regularthermal fuse 100 is connected to the high-voltage circuit, to be in series in the circuit which needs protection, so as to provide the over-temperature protection for the high-voltage circuit. - Furthermore, in order to realize the work of high-voltage direct-current thermal fuse in the embodiment of the invention, the fusing temperature of traditional
thermal fuse 100 should be configured to be less than the fusing temperature of high-voltage low-currentthermal fuse 300. The resistance of fuse-link in the current fuse should be configured to be more than that of high-voltage low-current thermal fuse. - Thus, when the circuit is a high-voltage high-current circuit, if the outside temperature reaches the fusing temperature of
thermal fuse 100, with the help of surface tension and fusing agent, fusible alloy wires 104 fuse off and shrink towards left and right leads on both ends. Due to the existence of the parallel circuit, the cutting off of fusible alloy wires 104 will not generate arcing. The current will go through the primary branch which is connected in parallel withthermal fuse 100, that is, the branch formed bycurrent fuse 200 connected in series with high-voltage low-currentthermal fuse 300. Since the resistance offuse 203 incurrent fuse 200 is more than that of high-voltage low-currentthermal fuse 300, fuse 203 fuses off first to cut off the parallel circuit. Sincecurrent fuse 200 with respect to the linear type fuse, at the fusing-off moment, the electric field intensity generated by the leads in parallel is more than multiple times, the diffusion and recombination process of the charged particles are more rapid under high electric field intensity, making the gap between the electrode leads quickly recovery to the insulation state, achieving the aim of extinguishing the arc. It has an arc extinguishing protection which is multiple times more than that of the normal fuse. - When the circuit is a high-voltage low-current circuit, if the outside temperature reaches the fusing temperature of
thermal fuse 100, after fusible alloy wires 104 fuse off, the current goes through the parallel circuit which is formed bycurrent fuse 200 and high-voltage low-currentthermal fuse 300. Since the current which goes through the parallel circuit is not sufficient to fuse offcurrent fuse 200, the parallel circuit is not cut off and the outside temperature keeps increasing. When it reaches the fusing temperature offusible alloy wires 303 of high-voltage low-currentthermal fuse 300, fusible alloy wires fuse off, and shrink towards both ends to become a ball, attaching to ends of twoleads fusible alloy wires 303 is too slow and the gap between high-voltage left lead,right lead fusible alloy wires 303 has a good fluidity. With the help of the elasticity of compressingspring 305,arc extinguishing sleeve 304 moves along the axis to cut offfusible alloy wires 303.Arc extinguishing sleeve 304 covers high-voltageleft lead 306 to insulate the discharging gap between high-voltageleft lead 306 and high-voltageright lead 307, so as to cut off the parallel circuit to prevent further damages to the electric appliance resulted from abnormal increasing of temperature or burning caused by the arc. -
Fig.4 shows the circuit schematic diagram of Embodiment 2 of the invention. As an expanded solution, in this Embodiment 2, the high-voltage direct-current thermal fuse is composed ofthermal fuse 100,current fuse 200, and high-voltage low-currentthermal fuse 300 as the same as those in Embodiment 1. Among others, high-voltage low-currentthermal fuse 300 is sequentially connected in series tocurrent fuse 200 to form the primary branch. Next, the primary branch is connected in parallel to both ends ofthermal fuse 100.Thermal fuse 100 is connected in series to the high-voltage circuit to be protected, so as to provide the over-temperature protection for the high-voltage circuit, which is not explained again here. - The differences between Embodiment 1 and Embodiment 2 lie in that: the high-voltage direct-current thermal fuse also includes N secondary branches, and each secondary branch includes the high-voltage low-current thermal fuse sequentially connected in series to the current fuse. Among others, the structure of the high-voltage low-current thermal fuse and that of the current fuse are the same as those of the primary branch, which is not explained again here. When N is equal to 1, the secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the primary branch. When N is more than 1, the Nth secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse which in the (N-1)th secondary branch. As
Fig.4 shows,Fig.4 includes two secondary branches. N is equal to 2. The first secondary branch includes high-voltage low-current thermal fuse 300' and current fuse 200' that are connected to each other in series sequentially. The second secondary branch includes high-voltage low-currentthermal fuse 300" andcurrent fuse 200" that are connected to each other in series sequentially. Among others, the first secondary branch is connected in parallel to both ends of high-voltage low-currentthermal fuse 300 in the primary branch. The second secondary branch is connected in parallel to both ends of high-voltage low-current thermal fuse 300' in the first secondary branch. - In fact, as an expanded solution, the number of the secondary branches is not limited to two in Embodiment 2, and can also be more. The next level of secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the last level of secondary branch. Using the manner of multi-parallel to the high-voltage low-current thermal fuse, the high-voltage low-current thermal fuse can be expendably applied in lightning protection module. Thus, the protection circuit is separated more effectively and timely to meet effective cutting off of the voltage.
- In additional, as another application solution, the high-voltage low-current thermal fuse in above Embodiment 1 and Embodiment 2 can both use the porcelain-tube type thermal fuse. The porcelain-tube type thermal fuse includes insulated porcelain tube, inside which fusible alloy wires that can melt at a predetermined temperature are encapsulated. The fusible alloy wires are welded between the right lead and left lead that are axisymmetric. The ends of two leads respectively extend outside the insulated porcelain tube in the direction which is away from the fusible alloy wires. Among others, any of the two leads can be sleeved by an arc extinguishing sleeve and a compressing spring. One end of the arc extinguishing sleeve contacts the fusible alloy wires, and the other end contacts the spring. One end of the spring is connected to the internal end face of the insulated porcelain tube in the compressed state. The elasticity of the spring which in configured in a compressed state is not sufficient to destroy the welding strength between the fusible alloy wires and left, right leads. Other settings are the same as those in Embodiment 1 or 2, which is not explained again here.
- Furthermore, as a basic application solution, high-voltage low-current
thermal fuse 300 in the embodiment of the invention can be used in the high-voltage direct-current circuit alone (e.g. connecting in series into the high-voltage direct-current circuit). When the circuit to be protected is the high-voltage direct-current circuit, if the outside temperature reaches the fusing temperature offusible alloy wires 303 in the high-voltage direct-currentthermal fuse 300,fusible alloy wires 303 fuse off and shrink towards both ends to become a ball, attaching to the ends of the leads whose reference numbers are 306, 307 respectively. With the generation of high-voltage arc, liquidizedfusible alloy wires 303 has a good fluidity.Arc extinguishing sleeve 304 moves along the axis to cut offfusible alloy wires 303 under the effect of the elasticity of compressingspring 305.Arc extinguishing sleeve 304 covers high-voltageleft lead 306 to insulate the special discharging gap between the high-voltageleft lead 306 and the high-voltageright lead 307, so as to cut off the parallel circuit to prevent further damages to other components in the circuit resulted from the abnormal increasing of temperature or burning caused by the arc. - As another expanded solution, the manner of using a regular thermal fuse connected in parallel to a current fuse can also be used to apply in the high-voltage direct-current circuit. Although the effect of the manner may not be optimal, it can realize the function of circuit cutting-off and arc extinguishing. If outside temperature reaches the fusing temperature of
thermal fuse 100, the cutting-off of fusible alloy wires 104 fuse off and shrink towards the right and left leads at both ends. Due to the existence of parallel circuit, the cutting-off of fusible alloy wires 104 will not generate the arc. The current will go through the current fuse connected in parallel tothermal fuse 100. When the current reaches a certain intensity and a certain temperature, fuse 203 ofcurrent fuse 200 will fuse off automatically to cut off the current, so as to achieve the function of protecting the circuit to operate safely. - For persons skilled in the art, it is easy to conceive of many modifications and other embodiments of the invention. In the invention, contents shown in the above descriptions and associated drawings have useful technical motivations. Thus, the embodiments of the invention only disclose preferable embodiments, and are not limited to specific embodiments disclosed, but also include various modifications and other embodiments within the scope of the claims. Although in the context, certain specific terms are used, they are only used for a general and descriptive sense, and do not constitute a limitation.
Claims (8)
- A high-voltage direct-current thermal fuse, at least comprises a high-voltage low-current thermal fuse connected to a high-voltage direct-current circuit;
wherein the high-voltage low-current thermal fuse comprises a casing,
a fusible alloy wire, encapsulated inside the casing, and
two leads, extending outside the casing,
wherein the fusible alloy wire is connected between the two leads; one of the leads being sequentially sleeved with an arc extinguishing sleeve and a spring; one end of the arc extinguishing sleeve contacting the fusible alloy wire; the other end of the arc extinguishing sleeve contacting the spring; one end of the spring being connected to the internal end face of the casing; and wherein, the spring is in a compressed state. - The high-voltage direct-current thermal fuse according to the claim 1, wherein the high-voltage direct-current thermal fuse further includes other thermal fuse, the high-voltage direct-current thermal fuse which is connected in series into the high-voltage direct-current circuit; the high-voltage low-current thermal fuse being connected in parallel to the first end and the second end of the other thermal fuse; the fusing temperature of the high-voltage low-current thermal fuse being higher than that of the other thermal fuse.
- The high-voltage direct-current thermal fuse according to the claim 2, wherein the high-voltage low-current thermal fuse is further connected in series to a current fuse to form a primary branch, the primary branch being connected in parallel to both ends of the other thermal fuse; the resistance of the current fuse is more than that of high-voltage low-current thermal fuse.
- The high-voltage direct-current thermal fuse according to the claim 3, wherein the current fuse is a tube fuse, which includes a metal fusing wire inside the tube and a tube body with both ends having a metal connecting terminal.
- The high-voltage direct-current thermal fuse according to the claim 3, wherein the current fuse is N-type current fuse, wherein the current fuse includes a fuse-link showing an N-type and two leads being connected between both ends of the fuse-link; the two leads extending from the top of the N-type of the fuse-link, which have a segment in parallel to each other.
- The high-voltage direct-current thermal fuse according to the claim 2, wherein the other thermal fuse is provided with at least one fusible alloy wire; the at least one fusible alloy wire is provided between the two leads.
- The high-voltage direct-current thermal fuse according to the claim 6, wherein the fusible alloy wire includes at least two pieces of fusible alloy wires; the at least two pieces of fusible alloy wires are provided in parallel or crossways between the two leads.
- The high-voltage direct-current thermal fuse according to any of claim 3 to claim 7, wherein the high-voltage direct-current thermal fuse also includes N secondary branches; the secondary branches including high-voltage low-current thermal fuse and the current fuse that are connected in series sequentially; wherein,when N is equaled to 1, the secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the primary branch; andwhen N is more than 1, the Nth secondary branch is connected in parallel to both ends of the high-voltage low-current thermal fuse in the (N-1)th secondary branch.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201420230161.5U CN203839326U (en) | 2014-05-07 | 2014-05-07 | High-voltage direct-current temperature fuse |
PCT/CN2015/078386 WO2015169223A1 (en) | 2014-05-07 | 2015-05-06 | High-voltage direct-current temperature fuse |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3244437A1 true EP3244437A1 (en) | 2017-11-15 |
EP3244437A4 EP3244437A4 (en) | 2018-04-25 |
Family
ID=51517133
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15788772.0A Withdrawn EP3244437A4 (en) | 2014-05-07 | 2015-05-06 | High-voltage direct-current temperature fuse |
Country Status (6)
Country | Link |
---|---|
US (1) | US9837236B2 (en) |
EP (1) | EP3244437A4 (en) |
JP (1) | JP6247402B2 (en) |
KR (1) | KR101825866B1 (en) |
CN (1) | CN203839326U (en) |
WO (1) | WO2015169223A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113573508A (en) * | 2021-07-22 | 2021-10-29 | 深圳市联明电源有限公司 | DC/DC power module with self-destruction disposable mounting pin |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN203839326U (en) | 2014-05-07 | 2014-09-17 | 厦门赛尔特电子有限公司 | High-voltage direct-current temperature fuse |
JP2017069355A (en) * | 2015-09-30 | 2017-04-06 | パナソニックIpマネジメント株式会社 | Control device |
US10312040B2 (en) * | 2016-05-11 | 2019-06-04 | Eaton Intelligent Power Limited | Modular circuit protection systems and methods |
CN108987210A (en) * | 2017-05-31 | 2018-12-11 | 厦门赛尔特电子有限公司 | A kind of controlled fuse of type high current disconnected fastly |
CN109216128A (en) * | 2017-06-30 | 2019-01-15 | 厦门赛尔特电子有限公司 | A kind of high voltage direct current thermal cut-off |
CN206976273U (en) | 2017-06-30 | 2018-02-06 | 厦门赛尔特电子有限公司 | A kind of HVDC thermal cut-off |
CN208093500U (en) * | 2018-04-03 | 2018-11-13 | 厦门赛尔特电子有限公司 | A kind of high-tension fuse |
CN108376632B (en) * | 2018-05-03 | 2024-01-16 | 杭州布雷科电气有限公司 | Self-triggering rapid breaker and triggering method thereof |
US11043344B2 (en) | 2018-05-23 | 2021-06-22 | Eaton Intelligent Power Limited | Arc flash reduction maintenance system with pyrotechnic circuit protection modules |
CN109243939B (en) * | 2018-08-27 | 2024-04-16 | 西安中熔电气股份有限公司 | Low-power consumption high response speed circuit protection device |
CN209993563U (en) * | 2019-01-16 | 2020-01-24 | 厦门赛尔特电子有限公司 | High-voltage fusing device |
CN209487458U (en) * | 2019-03-20 | 2019-10-11 | 厦门赛尔特电子有限公司 | Thermal Cutoffs |
CN209434140U (en) * | 2019-03-20 | 2019-09-24 | 厦门赛尔特电子有限公司 | Thermal Cutoffs |
US10895609B2 (en) * | 2019-05-09 | 2021-01-19 | Littelfuse, Inc. | Circuit protection device with PTC element and secondary fuse |
CN110492463A (en) * | 2019-09-29 | 2019-11-22 | 厦门赛尔特电子有限公司 | A kind of surge protection device with high breaking capacity |
KR102281423B1 (en) | 2019-12-19 | 2021-07-23 | 이율우 | Temperature fuse for high voltage DC current with shielding stability, and temperature fuse module using the same |
KR102512501B1 (en) | 2020-12-16 | 2023-03-20 | 이율우 | Temperature fuse for high voltage DC current, and temperature fuse module using the same |
KR102512504B1 (en) | 2021-01-12 | 2023-03-20 | 이율우 | Temperature fuse for high voltage DC current |
CN113436944A (en) * | 2021-07-05 | 2021-09-24 | 东莞市贝特电子科技股份有限公司 | Temperature fuse with novel sealing structure and preparation method |
KR102661886B1 (en) | 2022-03-17 | 2024-04-26 | 이율우 | Current fuse having an improved disconnection structure and a high pressure fuse molded body using the same |
CN114678238B (en) * | 2022-04-02 | 2023-01-20 | 江苏怡通控制***有限公司 | Protective structure of direct-current thermal protector |
CN114743846B (en) * | 2022-04-28 | 2024-04-26 | 西安五环特种熔断器有限公司 | Fireproof fuse capable of fusing and replacing wires |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3614699A (en) * | 1970-08-10 | 1971-10-19 | Mc Graw Edison Co | Protector for electric circuits |
US3810063A (en) * | 1972-02-25 | 1974-05-07 | Westinghouse Electric Corp | High voltage current limiting fuse including heat removing means |
US4308515A (en) * | 1980-02-07 | 1981-12-29 | Commercial Enclosed Fuse Co. | Fuse apparatus for high electric currents |
CA1189117A (en) | 1983-03-09 | 1985-06-18 | Terry R. O'brien | Electric fuse having high ambient temperature interrupting capability |
US4948828A (en) * | 1989-01-31 | 1990-08-14 | Cooper Industries, Inc. | Asbestos free material for gassing current limiting fuses |
CN2513223Y (en) * | 2001-12-05 | 2002-09-25 | 倪学锋 | Closed high voltage fuse |
JP4514669B2 (en) * | 2005-07-29 | 2010-07-28 | エヌイーシー ショット コンポーネンツ株式会社 | Protection device using thermal fuse |
DE102005040308B4 (en) * | 2005-08-24 | 2009-05-07 | Magna Electronics Europe Gmbh & Co.Kg | Thermal fuse, in particular for a power module of a motor vehicle, and power module with such a thermal fuse |
DE102008025917A1 (en) * | 2007-06-04 | 2009-01-08 | Littelfuse, Inc., Des Plaines | High voltage fuse |
US20110050384A1 (en) * | 2009-08-27 | 2011-03-03 | Tyco Electronics Corporation | Termal fuse |
CN102290301B (en) * | 2010-06-18 | 2014-04-02 | 厦门赛尔特电子有限公司 | High-current fuse |
JP5214066B1 (en) * | 2012-05-01 | 2013-06-19 | 三菱電機株式会社 | DC circuit breaker |
US9281152B2 (en) * | 2012-12-05 | 2016-03-08 | Eaton Corporation | Fuse with carbon fiber fusible element |
US10553386B2 (en) * | 2013-11-15 | 2020-02-04 | Eaton Intelligent Power Limited | High voltage, reinforced in-line fuse assembly, systems, and methods of manufacture |
CN203839326U (en) | 2014-05-07 | 2014-09-17 | 厦门赛尔特电子有限公司 | High-voltage direct-current temperature fuse |
-
2014
- 2014-05-07 CN CN201420230161.5U patent/CN203839326U/en not_active Expired - Fee Related
-
2015
- 2015-05-06 JP JP2016548051A patent/JP6247402B2/en active Active
- 2015-05-06 EP EP15788772.0A patent/EP3244437A4/en not_active Withdrawn
- 2015-05-06 US US15/125,585 patent/US9837236B2/en active Active
- 2015-05-06 KR KR1020167027772A patent/KR101825866B1/en active IP Right Grant
- 2015-05-06 WO PCT/CN2015/078386 patent/WO2015169223A1/en active Application Filing
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113573508A (en) * | 2021-07-22 | 2021-10-29 | 深圳市联明电源有限公司 | DC/DC power module with self-destruction disposable mounting pin |
CN113573508B (en) * | 2021-07-22 | 2022-04-26 | 深圳市联明电源有限公司 | DC/DC power module with self-destruction disposable mounting pin |
Also Published As
Publication number | Publication date |
---|---|
JP6247402B2 (en) | 2017-12-13 |
WO2015169223A1 (en) | 2015-11-12 |
CN203839326U (en) | 2014-09-17 |
US20170004947A1 (en) | 2017-01-05 |
US9837236B2 (en) | 2017-12-05 |
JP2017508245A (en) | 2017-03-23 |
EP3244437A4 (en) | 2018-04-25 |
KR101825866B1 (en) | 2018-02-05 |
KR20160142307A (en) | 2016-12-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9837236B2 (en) | High-voltage direct-current thermal fuse | |
US8816812B2 (en) | Varistor fuse element | |
TWI521558B (en) | Fuse | |
JP2014007134A (en) | High breaking capacity fuse | |
CN203398063U (en) | Fuse in the shape of n | |
US20170222426A1 (en) | Surge protection device with an independent chamber comprising a fuse for overcurrent protection | |
US9490096B2 (en) | Medium voltage controllable fuse | |
US4527215A (en) | Valve type voltage arrester device | |
KR20100090288A (en) | Surge arrester having thermal overload protection | |
US2504438A (en) | Circuit interrupter | |
CN101836340A (en) | Switching device for limiting damage of surge arresters, such as varistors, spark gaps or the like | |
US11621138B2 (en) | High-voltage fusing apparatus | |
CN207183192U (en) | A kind of current over-load protector structure | |
JP6247002B2 (en) | A device that can be integrated into a contactor to protect an electrical circuit supplied with alternating current | |
WO2015188752A1 (en) | Novel thermal-protection metal-oxide varistor and surge protector | |
US2251409A (en) | Electric fuse | |
CN220553811U (en) | Thermal protection module and thermal protection type photovoltaic connector | |
CN203787378U (en) | Over-current protector with voltage-releasing function | |
JP2006179842A (en) | Thunder protection equipment capable of separating body on breaking down metal oxide varistor | |
CN206758395U (en) | Vacuum fastp-acting fuse | |
CN209496801U (en) | A kind of high-voltage and current-limitation fuse that can easily be accommodated | |
JP3128342U (en) | Anti-electric shock insulation fuse | |
KR200267634Y1 (en) | Thermal-cut-off varistor | |
CN116885665A (en) | Thermal protection module and thermal protection type photovoltaic connector | |
KR20220101805A (en) | Temperature fuse for high voltage DC current |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20160922 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 20180322 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: H01H 85/38 20060101AFI20180316BHEP |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
INTG | Intention to grant announced |
Effective date: 20180709 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20181120 |